Brake drum (axle) retainers for Model A Mechanical Braking

[Cory Moffat]

I am gearing up to change my ring and pinion to 3.54s this spring in my 1930 coupe with original mechanical brakes.
Over the years its always been in the back of my mind what if a Axle broke and my Hub ran off.
So I am thinking of making up some Axle retainers and install them while I am at it.


I have looked around and I cant really find anything about these retainers being mounted on original Model A mechanical backing plates with cast iron drums.
However I see lots of talk about mounting on the 1932 backing plate.


I got it figured out how I am going to make and mount them.


My Question is do you think they are needed? Has anyone here ever broke a axle and lost a hub?



Anyone else done this and do you have any pictures to share? It would be appreceated.


There is lots of great minds here and someones input probably will improve on what I am thinking. You never know.

[mercman from oz]

This is what you are looking for.

[Joe K]

Axles ARE subject to breakage. A common original place was from stress concentration at the "groove" that the axle shaft seal makes.

Another failure point that has been noted are the aftermarket "replacement" axles which are made with a loose gear probably welded to the axle shaft. This part was originally made "solid" by mushrooming an axle shaft and then shaping/cutting the gear from the blob at the end.

If I had axles in the repop style, I would certainly be interested in a clip such as is shown.

Axles I use, I generally grind down the shaft while held between centers to remove the "stress transition" at the seal groove somewhat. One has to go at this judiciously since one IS reducing the "torque area" of the shaft in so doing. An "ease of stress concentration" is probably more important than entire groove removal.

Joe K

[denis4x4]

Speedway Motors has those.

[Cory Moffat]

That is a 1932 hydraulic backing plate that is flat and has bolts to mount the brake cylinder. The model A has a dished backing plate. No bolts in that position either. Just rivets for the brake springs are there. Different beast isn't it? Has anyone actually put these on a original mechanical braking model A?

[Fullraceflathead]

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You would have to custom make them for the factory model A. backing plate but it would not be very difficult to do.

[katy]

[QUOTE=Cory Moffat;2373405My Question is do you think they are needed? Has anyone here ever broke a axle and lost a hub?[/QUOTE]

I had that happen on a Model T.

If there is slop in the wheel bearing, it puts stress on the axle at the point where the axle exits the bearing.

[BRENT in 10-uh-C]

Let me see if I can find a picture of how we made them when I was dirt track racing Model-As. Basically we welded a stud to the backside of the Housing (Backing) Plate and fabricated a clip that went over the edge of the drum in opposite sides.

[Fullraceflathead]

It sounds like Brent definitely has the right idea!!!

[Cory Moffat]

Seems like not done too often. But I think it would be a good idea. I will bend some up and post them mounted when I get around to it.

[Bob Bidonde]

I have experienced two rear axle failures in my Model A's. One caused the departure of the left rear wheel including the brake drum because the axle's threads were stripped and the nut came off. The second failure was a fatigue of the left axle shaft at the top of the key-way that did not cause the wheel to come off, but it could have. I think a simple bracket to retain a rear wheel in the event of an axle failure is a good idea for a Model "A" Speedster, a Model "A" with a hi-po engine and a touring Model "A."

[old31]

Bob, do you think those hole shots that you have been doing have anything to do with the broken axles?

[Synchro909]

IMO, the best way to prevent your wheel overtaking you is to make sure your rear hubs are in good order. It is worn hubs that cause axle breakage in the first place.

[Cory Moffat]

Thought I would make up the retainers before I dropped the rear end. There is quite the angle on the back of the retainer to follow the contour of the backing plate. The cage nut Plates will be tack welded to the inside of the backing plate after drilling mounting bolt holes. The retainers are just tacked together right now for fitting purposes. I will feel better with them installed as my supply of spare axles are used and pushing 100 years old. Even if they have been magnafluxed. What could possibly go wrong? Well time to drop the rear end and install my new ring and pinion.

[Cory Moffat]

[katy]

I would think that "squared off" as in post #2 would be stronger that the "angled" style that you show.

[Jim Brierley]

Originally Posted by Joe K

Axles ARE subject to breakage. A common original place was from stress concentration at the "groove" that the axle shaft seal makes.

Another failure point that has been noted are the aftermarket "replacement" axles which are made with a loose gear probably welded to the axle shaft. This part was originally made "solid" by mushrooming an axle shaft and then shaping/cutting the gear from the blob at the end.

If I had axles in the repop style, I would certainly be interested in a clip such as is shown.

Axles I use, I generally grind down the shaft while held between centers to remove the "stress transition" at the seal groove somewhat. One has to go at this judiciously since one IS reducing the "torque area" of the shaft in so doing. An "ease of stress concentration" is probably more important than entire groove removal.

Joe K

Grinding the axle, full length, is a good idea. I do this on all the rear ends that I do (did, don't do much of anything anymore). I once found a crack after grinding, that I did not see prior to grinding.

I have never personally lost a wheel from a broken axle, but it can happen. All racing organizations require a safety device to prevent this.

[old31]

Does anyone make a axle retainer for the A?

[Cory Moffat]

Well I installed my hub retainers. I opted to install them on the bottom as there is lots of room down there.

[katy]

Lookin' good.